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20 results

  • Cellular and molecular alterations of buffalo oocytes cultured under two different levels of oxygen tension during in vitro maturation

  • Nasser Ghanem, Dalia Abd-El Rahman Ahmed, Sherif Mohamed Dessouki, Marwa Said Faheem, Ahmed Yehia Gad, Jaana Peippo, Ashraf Hesham Barkawi
  • Journal: Zygote / Volume 29 / Issue 4 / August 2021
  • Published online by Cambridge University Press: 24 February 2021, pp. 314-324

  • This study was conducted to monitor the cellular and molecular changes of buffalo cumulus–oocytes complexes (COCs) cultured under high or low oxygen levels. Morphologically good quality COCs (n = 1627) were screened using brilliant cresyl blue (BCB) staining and placed into three groups (BCB+, BCB− and control). All groups of COCs were cultured under low (5%) or high (20%) oxygen tensions. Intracellular and molecular changes including oocyte ultrastructure, lipid contents, mitochondrial activity and transcript abundance of genes regulating different pathways were analyzed in the matured oocyte groups. The results revealed that oxygen tension did not affect cumulus expansion rates, however the BCB+ group had a higher (P ≤ 0.05) expansion rate compared with the BCB− group. BCB− oocytes recorded the lowest meiotic progression rate (P ≤ 0.05) under high oxygen levels that was linked with an increased level of reactive oxygen species (ROS) compared with the BCB+ oocytes. Ultrastructure examination indicated that BCB+ oocytes had a higher rate of cortical granules migration compared with BCB− under low oxygen tension. In parallel, our results indicated the upregulation of NFE2L2 in groups of oocytes cultured under high oxygen tension that was coupled with reduced mitochondrial activity. In contrast, the expression levels of MAPK14 and CPT2 genes were increased (P ≤ 0.05) in groups of oocytes cultured under low compared with high oxygen tension that was subsequently associated with increased mitochondrial activity. In conclusion, data from the present investigation indicated that low oxygen tension is a favourable condition for maintaining the mitochondrial activity required for nuclear maturation of buffalo oocytes. However, low-quality oocytes (BCB−) responded negatively to high oxygen tension by reducing the expression of gene-regulating metabolic activity (CPT2). This action was an attempt by BCB− oocytes to reduce the increased levels of endogenously produced ROS that was coupled with decreased expression of the gene controlling meiotic progression (MAPK14) in addition to nuclear maturation rate.

Pediatric Head and Neck Pathology
  • Robert O. Greer, Robert E. Marx, Sherif Said, Lori D. Prok
  • Published online: 26 June 2017
  • Print publication: 20 October 2016
  • This unique reference provides a comprehensive guide to pediatric head and neck pathology in patients up to the age of 21. Chapters take a clinicopathologic approach, offering insight into the pathobiology, diagnosis and treatment of both common and rare disorders. Imaging studies and immunohistochemical techniques are discussed alongside accepted and emerging molecular tools. The authors' holistic approach ensures coverage of the surgical management principles that pathologists must understand, particularly when called upon to diagnose odontogenic tumors and cysts, as well as benign and malignant salivary gland neoplasms. The book is richly illustrated in color throughout. Each copy of the printed book is packaged with a password, providing online access to the book's text and image library. Written by leaders in head and neck pathology and surgery, this is an essential guide to solving the diagnostic dilemmas that pathologists and clinicians encounter in the assessment of pediatric head and neck disease.